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Abstract Introduction: IEC-HS is an emerging and potentially life-threatening complication in multiple myeloma (MM) patients (pts) treated with CAR-T therapies. We conducted a retrospective, multi-institutional analysis to define the features and outcomes of IEC-HS after ide-cel or cilta-cel in the real-world setting. Methods: This study used data from 15 centers within the US Multiple Myeloma Immunotherapy Consortium for patients with relapsed/refractory MM (RRMM) who received commercial cilta-cel or ide-cel. IEC-HS was defined by each center based on diagnostic criteria (Hines et al, TCT 2023). Kaplan-Meier and multivariable Cox models were used for time-to-event outcomes while logistic regression was used for categorical outcomes. Results: Of 1502 RRMM pts who received either ide-cel (n=712) or cilta-cel (n=790), 74 patients (4.9%) had a provider-determined diagnosis of IEC-HS. Product-specific incidences were 2.9% for ide-cel and 6.7% for cilta-cel. The median time from CAR-T infusion to IEC-HS onset was 9.5 days (range 2-37 days). IEC-HS-related clinical findings (Hines et al, 2024) included cytopenias (95%), elevated soluble IL-2R levels (79%), fever (76%), elevated LDH (71%, median 1,800 U/L), hypofibrinogenemia (70%), hypertriglyceridemia (65%), ICANS (63%), hepatic transaminase elevation (56%), pulmonary involvement (46%), renal insufficiency (29%), hyperbilirubinemia (22%), and hemophagocytosis in bone marrow (6%). The median interval from peak CRS to IEC-HS onset was 4 days (IQR 1–6). Some variables, such as splenomegaly and coagulopathy, were not systematically collected. Nearly all pts received pharmacologic intervention: corticosteroids (94%, n=59), anakinra (76%, n=48), tocilizumab (71%, n=45), emapalumab (13%, n=8), ruxolitinib (16%, n=10), or etoposide (3%, n=2). Only one pt (2%) did not receive any IEC-HS therapy. Among those evaluable for outcomes, 58% (n=35) improved, 12% (n=7) developed further CAR-T-related complications (e.g., recurrent IEC-HS, delayed neurotoxicity), and 30% (n=18) had no therapeutic response and died. Compared to non-IEC-HS pts (n=1,428), those with IEC-HS were younger (median age 63 vs 66), male (61% vs 57%), and more frequently received cilta-cel (72% vs 52%, all p<0.01). They had higher rates of triple-class (81%) and penta-refractory (43%) disease, greater pre-treatment bone marrow plasma cell burden (40% vs 6%), and higher baseline ferritin (1058 vs 208 ng/mL). Prior autologous SCT was less common, and advanced R-ISS stage was more prevalent. IEC-HS was associated with dramatically worse PFS and OS: with cilta-cel, median PFS was 6.5 months (mo) with IEC-HS (vs 33.1 without); for ide-cel, 8.9 vs 11.4 mo. Median OS for cilta-cel IEC-HS pts was 9.6 mo (not reached in non-IEC-HS pts); for ide-cel IEC-HS, 19.6 mo (vs 40.8 mo). Multivariable analysis confirmed IEC-HS as an independent predictor of shorter PFS (HR 1.88, 95% CI 1.29–2.74, p=0.0011) and OS (HR 2.30, 95% CI 1.39–3.83, p=0.0013). Notably, IEC-HS was not associated with lower response rates – either best CR (63.9% vs 64.0%, p=0.71) or ORR (91.8% vs 90.9%, p=0.97). Cilta-cel pts had a higher probability of achieving a deep (CR) response, regardless of IEC-HS status. Grade > 3 CRS occurred in 14% (n=3/21) of ide-cel and 15% (n=8/52) of cilta-cel IEC-HS pts, versus 2% (n=12/691) and 2% (n=13/737) in non-IEC-HS pts, respectively. Any-grade ICANS was observed in 67% (n=14/21) of ide-cel and 55% (n=29/52) of cilta-cel IEC-HS cases, compared to 26% (n=179/690) and 20% (n=148/738) in non-IEC-HS. Grade ≥3 ICANS occurred in 29% (n=6/21) of ide-cel and 26% (n=14/52) of cilta-cel IEC-HS cases, relative to 4% (n=25/690) and 4% (n=27/738) in pts without IEC-HS. Severe infections were also more common: 71% (n=15/21) of ide-cel and 53% (n=28/52) of cilta-cel IEC-HS pts experienced at least one infection, compared to 31% (n=214/691) and 29% (n=217/737) in non-IEC-HS groups. Conclusions: IEC-HS is an uncommon but severe and early complication after CAR T-cell therapy for RRMM. Despite similar ORRs with or without IEC-HS, IEC-HS was associated with significantly worse PFS and OS for both ide-cel and cilta-cel. These findings support the need for vigilant monitoring and potential preemptive treatment strategies to better manage this syndrome.

Abstract Background: Real-world data suggest that safety and efficacy of ide-cel and cilta-cel mirror data from pivotal trials, yet older adults remain underrepresented. We report outcomes of the largest cohort of RRMM patients aged ≥75 years receiving CAR-T and compare them with propensity-matched younger patients. Methods: We retrospectively analyzed RRMM patients receiving standard-of-care BCMA CAR-T at 15 centers from the US Myeloma Immunotherapy Consortium between May 2021 and December 2024. Patients ≥ 75 years were 2:1 propensity-matched to patients < 75 based on CAR-T product, sex, performance status, extramedullary disease, baseline ferritin, penta-refractory status, bridging therapy, prior autologous SCT and lines of therapy. Continuous outcomes were analyzed with multivariable linear regression, binary outcomes with logistic regression, and time-to-event endpoints with Cox proportional-hazards models. We estimated average treatment effects via G-computation, using cluster-robust standard errors to account for the matched sets. Results: After 2:1 propensity matching, the cohort included 194 patients ≥ 75 years (cilta-cel: 64 and ide-cel: 130) and 388 patients < 75 years (cilta-cel: 128, ide-cel: 260). Median ages were 78 (range: 75-90) for the older cohort vs 65 (range: 35-74) for the younger cohort. The older cohort had a higher frequency of t(14;16) (9% vs. 3%, p = 0.005), lower baseline ferritin (151 vs. 196 ng/mL, P = 0.046), and lower likelihood of prior ASCT (57% vs. 71%, P = 0.001). Median prior lines of therapy were 5. Median follow-up time for ≥ 75 and < 75 groups for cilta-cel was 11.5 and 11 months and for ide-cel was 16 and 24.3 months, respectively. ORR did not differ amongst the older vs younger patients: cilta-cel (97% vs. 97%) and ide-cel (90% vs. 88%).For patients ≥ 75 years, median PFS with cilta-cel was 28.7 months (95% CI: 13.3–NR) and with ide-cel was 16.4 months (95% CI: 12.1–22.4). In patients < 75 years, median PFS was not reached for cilta-cel but was 11.5 months (95% CI: 9.6–12.7) for ide-cel, reflecting inferior PFS with ide-cel in the younger group (HR 0.4, 95% CI 0.3–0.6). On sensitivity analysis by Cox proportional hazards model, we did not observe any statistically significant differences in PFS in older vs younger patients receiving cilta-cel, although older patients paradoxically had better PFS with ide-cel compared to their matched younger cohort. In the cilta-cel cohort, HR for PFS for older vs younger patients was 1.48 (95% CI:0.77-2.84; p=0.2) and in the ide-cel cohort it was 0.7 (95% CI: 0.5, 0.98; p=0.04). Median OS was reached only in the < 75-year ide-cel cohort at 40 months (95% CI: 32.5–43.5). Rates of CRS were similar, with any-grade (grade ≥3) CRS seen in 74% vs 78% (0% vs. 0.8%) of cilta-cel recipients and 86% vs. 87% (3.1% vs. 1.5%) of ide-cel recipients in the older vs younger groups, respectively. ICANS rates were 21% vs. 20% for cilta-cel (p = 0.79) and 29% vs 20% for ide-cel (p = 0.07), with similar rates of grade ≥ 3 ICANS. In the cilta-cel cohort, Parkinsonian delayed neurotoxicity (DNT) occurred in 3/62 (4.8%) older patients and 6/128 (4.7%) younger patients. Similarly, other non-Parkinsonian DNT rates were similar across age groups, with 6.4% vs 5.5% in older vs younger cilta-cel cohort and 0% vs 1% in the older vs younger ide-cel cohort. Rates of IEC-HS, and infections were comparable across the cohorts. There was no difference in hospital length of stay and ICU admission rate between products within either age cohort. The overall non-relapse mortality (NRM) was 6.7% for patients ≥ 75 years and 6.2% in patients < 75 years. For cilta-cel, NRM in older vs younger cohort was 9.4% vs 4.7% (p= 0.96) and for ide-cel it was 5.4% vs 6.9%, respectively (p= 0.65). Conclusion: Appropriately selected older adults (≥75 years) receiving CAR-T therapy for RRMM can derive a similar efficacy benefit with CAR-T as a propensity-matched younger cohort, without any increased signal of toxicity including CRS, ICANS or delayed NT. NRM was numerically greater, but not statistically significant, in older adults receiving cilta-cel. Median PFS with cilta-cel and ide-cel in older adults were 28.7 months and 16.4 months with median OS not reached and 40 months, respectively. Older adults, ≥75 years old, should not be excluded from CAR-T therapy solely due to advanced age. Overall, cilta-cel was not associated with worsened toxicities in older adults and may offer better PFS.

Abstract Background: Parenteral DNA methyltransferase inhibitors (DNMTi) such as azacitidine and decitabine (DEC), including an attenuated 3-day regimen, are recommended in the NCCN Guidelines for patients (pts) with lower-risk myelodysplastic syndromes (LR-MDS) with clinically significant cytopenias. However, parenteral administration requires frequent clinic visits, which imposes a substantial burden on pts, particularly those requiring long-term therapy. Oral DMTIs offer more flexible dosing and maintenance of pts' autonomy. Oral DEC-cedazuridine (DEC-C) is a fixed-dose combination tablet containing DEC (35 mg) and cedazuridine (100 mg). ASTX727-03 (NCT03502668) is a randomized, open-label, multicenter, phase 1/2 clinical trial evaluating safety, efficacy, and pharmacokinetics (PK) of various DEC-C doses and regimens in pts with LR-MDS. Phase 1 identified a 5-day regimen of DEC 10 mg/cedazuridine 100 mg as the optimized low-dose (LD) regimen. Phase 2 compares this LD regimen with the attenuated standard-dose (SD) regimen. Here, we report phase 2 results on efficacy, safety, PK, and pharmacodynamic (PD) data. Methods: Adults (aged ≥18 years) with International Prognostic Scoring System (IPSS) low-risk or Intermediate-1 MDS, ECOG PS 0−2, and ≥1 cytopenia or red blood cell (RBC) transfusion dependence were randomized 1:1 to receive oral DEC-C LD (10 mg x 5 days) or SD (35 mg x 3 days). The primary endpoint was hematologic response. Secondary endpoints included PK, PD (by LINE-1 demethylation), time to bone marrow blasts >5%, leukemia-free survival (LFS), overall survival (OS), and safety. Results: As of October 31, 2024, 81 pts were treated (LD arm: n=40; SD arm: n=41) and completed a median of 8.8 months on treatment. At cutoff, 17 (42.5%) and 12 (28.6%) LD and SD pts, respectively, were still continuing the study; 9 (22.5%) and 6 (14.6%) pts respectively, had discontinued treatment due to hematopoietic stem cell transplant. Median age was 70 (LD) and 75 (SD) years; 75.0% (LD) and 68.3% (SD) had IPSS Int-1 risk MDS and 60.0% vs 41.5% had IPSS-Molecular Lower-Risk MDS (very low, low, or moderate-low). Low-risk prognostic scoring system risk distribution was similar: Category 1 (2.5% vs 4.9%), Category 2 (47.5% vs 46.3%), and Category 3 (50.0% vs 48.8%). After a median follow-up of 29.3 months, median OS was 23.9 months (95% confidence interval [CI]: 13.0, not estimable [NE]) in the LD arm vs 26.0 months (95% CI: 19.4, 28.5) in the SD arm. Median LFS was 23.8 months (95% CI: 13.0, NE) and 25.7 months (95% CI: 17.8, 26.5), respectively. Hematologic improvement per International Working Group 2006 criteria was achieved in 27.5% (LD) and 26.8% (SD) of pts. Among RBC transfusion–dependent pts, 52.4% (LD) and 37.5% (SD) achieved ≥56-day independence and 47.6% (LD) and 20.8% (SD) achieved ≥112-day independence. Pts received a median of 10 (LD) and 9 (SD) cycles. Delayed cycles occurred in 72.5% (LD) vs 82.9% (SD) of pts; dose reductions occurred in 40.0% (LD) and 46.3% (SD) of pts. Both treatment regimens caused a decrease in blood counts, reaching a nadir before recovering in each cycle. Neutropenia was more pronounced during early cycles and was more severe in the SD arm. Blood counts across all lineages remained stable or improved through ≥12 cycles with the LD arm, suggesting a more favorable safety and tolerability profile. Grade ≥3 adverse events (AEs) occurred in 85.0% and 90.2% of pts in the LD and SD arms, respectively; treatment discontinuation due to AEs occurred in 2.5% and 17.1% of pts, respectively. Most commonly reported treatment-emergent AEs were anemia (42.5% LD, 39.0% SD), fatigue (32.5% LD, 43.9% SD), and thrombocytopenia (37.5% LD, 39.0% SD). Three deaths occurred in the trial: 2 in the LD arm, which were both unrelated to study treatment, and 1 in the SD arm (Pseudomonal bacteremia in Cycle 1), which was treatment related. Total AUC0–24 was 199 ng*h/mL in the LD arm and 465 ng*h/mL in the SD arm; AUC for all cycles of the LD arm was approximately half of the SD arm. Maximal % LINE-1 demethylation rate was lower with LD than SD, but narrowed by Cycle 3. Conclusion: LD oral DEC-C demonstrated comparable clinical benefit to SD oral DEC-C, with improved safety and tolerability, including fewer dose modifications and less severe myelosuppression. These findings support LD DEC-C as a potential optimal regimen for pts with LR-MDS. Clinical trial registration: NCT03502668

Abstract Introduction: The attainment of rapid and deep hematologic responses is key to restoring organ function and reducing mortality in AL amyloidosis. Despite the introduction of anti-CD38 monoclonal antibodies, ~50% of AL patients will respond sub optimally to 1st-line therapy, and many will relapse. Bispecific T-cell engagers (TCEs) have produced unprecedented outcomes in relapsed myeloma, and whether they can be safely applied to AL amyloidosis is a key clinical question. Methods: A multicenter retrospective study involving 9 US academic medical centers within the US Multiple Myeloma Immunotherapy Consortium. We included patients with systemic AL amyloidosis who received bispecific TCE therapy targeting either BCMA or GPRC5D to investigate the safety, and efficacy of this approach. Results: Between February 2023 and March 2025, we identified 29 patients with AL amyloidosis treated with TCEs (n=19 teclistamab, n=6 elranatamab, n=4 talquetamab). The median age was 72-years (IQR: 66, 75), with a female predominance (59%, n=17). Most patients had lambda light-chain isotype (59%, n=17), 31% (n=9) had t(11;14). Diagnostic bone marrow plasma cell (BMPC) burden was unknown in 6 cases, of the remaining cases 74% had ≥10% and 65% had ≥20% BMPCs. Ten patients (34%) had either ≥60% BMPCs at diagnosis or an involved FLC ratio >100 prior to TCE. The median number of prior lines was 5 (IQR: 4, 6), all patients had previous anti-CD38 monoclonal antibody exposure, 55% (n=16) had received an autologous stem cell transplant, and 28% (n=8) had received prior BCMA-directed therapy (n=4 antibody drug conjugates [ADCs], n=3 CAR T, n=1 ADC + TCE). Immediately prior to TCE therapy, 8% (n=2) were stage 3A and 19% (n=5) were stage 3B according to the European modification of the Mayo 2004 prognostic score. Staging was unknown in n=3 cases. Regarding organ involvement, 66% (n=19) had cardiac, 59% (n=17) had renal, 24% (n=7) had gastrointestinal (biopsy-proven), 10% (n=3) had peripheral nerve and 3% (n=1) had autonomic nerve involvement. The rate of cytokine release syndrome (CRS) was 45% (Grade 1, G1: n=8, Grade 2, G2: n=5, Grade ≥3,G3+: n=0), and immune cell associated neurological syndrome (ICANS) was 14% (G1: n=3, G2: n=1, G3+: n=0). Seven patients (24%) received tocilizumab as treatment, a further one patient received prophylactic tocilizumab. One-third of the cohort experienced at least one infection (n=10), and 20 (n=6) experienced a ≥grade 3 infection. The overall response rate was 76% (n=22) by AL amyloidosis response criteria, including a 66% (n=19) complete response (CR), 7% (n=2) very good partial response (VGPR), and 3% (n=1) partial response (PR) rate. Two patients did not undergo disease reassessment; one due to an early treatment-emergent death, and one who was lost to follow-up before cycle 2. Among responders, the median time to a VGPR or better was 29 days (IQR: 18, 56). At a median follow up of 8.8 months, the 1-year overall survival rate was 77% (95%CI: 62%-95%). Of the 6 deaths which occurred, 3 occurred while on TCE therapy (VF arrest during step up not associated with CRS, cardiac failure, and infectious complication), and 3 deaths occurred off therapy (unknown, progressive disease, and as a complication of surgery). Of 14 patients eligible for cardiac response assessment at the time of TCE therapy (NTproBNP>650 OR BNP>150), 9 (64%) obtained a response (CarPR=4, CarVGPR=2, CarCR=3). Of 4 patients eligible for renal response assessment at the time of TCE initiation (>1g proteinuria/day), all 4 patients obtained a response (RenPR=1, RenVGPR=2, RenCR=1). Conclusion: This is the largest cohort of TCE therapy in AL amyloidosis. TCE therapy produced a high rate of rapid and deep haematological responses. Despite a high prevalence of cardiac and renal involvement, rates of CRS were low with no grade ≥3 events, however, infectious complications were frequent. Non-relapse mortality reflected our cohort's advanced disease and prior treatment, including 2 deaths (7%) unequivocally related to cardiac causes. Although follow-up was limited, there was a high rate of early organ responses, consistent with the deep hematological response rates observed. Although our cohort exhibited overlapping features with multiple myeloma, such as a high baseline plasma cell burden, the pattern of organ involvement was consistent with typical AL amyloid populations, supporting the broader application of this therapy in AL amyloidosis.

Abstract Introduction: Multiple myeloma (MM) accounts for nearly 20% of all hematologic cancers in the US and remains a substantial clinical burden, with patients (pts) requiring multiple lines of therapy (LOT). While advances such as BCMA-directed CAR T-cell therapy have improved outcomes, challenges persist, including disease relapse, treatment toxicities (CRS, ICANS, and non-ICANS neurotoxicities), and access. AZD0120 (formerly GC012F) is a first-in-class autologous BCMA/CD19 dual-targeting CAR T-cell therapy using the FasTCAR rapid manufacturing platform that preserves the naive and central memory T-cell phenotypes with marked in vivo proliferative capacity. Phase 1 investigator-initiated trials in China demonstrated deep, durable responses and a favorable safety profile following single-infusion AZD0120 in newly diagnosed and relapsed/refractory MM (RRMM) (Du J, et al. EHA 2024 and ASCO 2023). Here, we report for the first time preliminary phase 1b results from DURGA-1, an ongoing phase 1b/2 clinical trial evaluating the safety and efficacy of AZD0120 in pts with RRMM. Methods: This open-label, single-arm, US-based, multicenter study (NCT05850234) evaluated the safety/tolerability of 2 dose levels (DL) of AZD0120 in pts with RRMM along with preliminary efficacy. Eligible ptswere aged ≥18 y with RRMM (3+ prior LOT [pLOT] including a proteasome inhibitor, immunomodulatory drug, and anti-CD38 antibody), ECOG PS 0–1, and documented evidence of progressive disease. Exposure to BCMA-directed therapy ≥6 mo with best response of PR or better was permitted. Pts underwent lymphodepletion followed by a single infusion of AZD0120. Pts in DL1 received 1x105 cells/kg; DL2 received 3x105 cells/kg. Dose escalation and recommended phase 2 dose (RP2D) were determined by a safety review committee. Phase 1b primary objectives included safety/tolerability and RP2D determination; secondary objectives included efficacy, cellular kinetics (CK), and pharmacodynamics. Results: As of data cutoff (DCO) on 18 July 2025, a total of 25 pts received infusion of AZD0120 (n=12 DL1; n=13 DL2). The median age was 64 y (range 44–78), median pLOT was 4 (range 3–7), 72% were triple-class refractory, 20% had prior BCMA CAR T-cell therapy, 4% had prior teclistamab, 28% had high-risk cytogenetic features [del(13q), del(17p13), t(4;14), t(14;16), amp(1q)], and 8% had extramedullary plasmacytomas. The median time from apheresis to release was 14 d (range 10–30). Median time from apheresis to infusion was 28 d (range 19–44) with 5 pts receiving bridging therapy. Median follow-up was 1.4 mo (range 0–19.3). No dose-limiting toxicities were reported for either dose. The most common treatment-emergent AEs (TEAEs, any grade) were CRS (64%), neutrophil count decreased (56%), and anemia (32%). The most common grade ≥3 TEAEs were neutrophil count decreased (52%), lymphocyte count decreased (32%), and white blood cell count decreased (32%). CRS was reported in 75% of pts at DL1 (all grade 1) and 54% at DL2 (46% grade 1; 8% grade 2), with no cases of grade ≥3 CRS. Median time to CRS onset (DL1/DL2) was 9 d (range 2–11), with a median duration of 2 d (range 1–4); 12 pts (48%) received tocilizumab for CRS management and 12% received dexamethasone. No cases of ICANS, related non-ICANS neurotoxicity, IEC-colitis, or secondary primary malignancies have been reported. There have been no deaths. For efficacy-evaluable patients (n=15), ORR was 100% (33% sCR, 47% VGPR, 20% PR). CR rates in evaluable pts were 30% in DL1 (n=10) and 40% in DL2 (n=5); median time to response was 0.9 mo for both DLs (range 0.9–1.9 DL1; 0.6–1.8 DL2). All MRD-evaluable pts (n=5 DL1; n=3 DL2; DCO 01 July 2025) were MRD-negative by NGS at a sensitivity of 10-5. Three pts in DL1 with ≥12 mo follow-up maintained MRD negativity. Consistent with robust in vivo expansion, CK analysis from 16 evaluable pts (DCO 12 June 2025) demonstrated a median Tmax of 13 d post-infusion with a median Cmax of 85,266 copies/mg gDNA. Median persistence was 42 d (range 13–273). Updated clinical data with additional follow-up will be presented. Conclusion: Preliminary phase 1b results demonstrated AZD0120 was well tolerated, with a low incidence of serious AEs, no grade ≥3 CRS, and no ICANS. FasTCAR-manufactured AZD0120 had expectedin vivo expansion, which may have resulted in the predictable CRS profile. A single infusion of AZD0120 achieved early, deep responses with 100% MRD negativity from 4L+ triple-class‒exposed pts with RRMM.

Abstract Introduction: Bispecific T-cell engagers (TCE) targeting BCMA (teclistamab, elranatamab) and GPRC5D (talquetamab) are important therapeutic options in relapsed/refractory MM (RRMM). However, data on the independent prognostic impact of individual cytogenetic abnormalities and functional high-risk MM on outcomes with TCEs remains limited. Methods We included RRMM patients treated with BCMA TCEs (teclistamab, elranatamab) and talquetamab across 15 centers in the US. Patients where TCEs were used only as bridging therapy to CAR-T were excluded. High-risk cytogenetic abnormalities (HRCA) included del(17p), t(4;14), t(14;16), 1q gain/amplification (1q21+), del(1p) before initiation of TCE. Functional high-risk disease (FHRMM) was defined as PFS <18 months with frontline therapy. Extramedullary disease (EMD) included visceral or soft tissue disease and excluded paraskeletal disease. Progression-free survival (PFS) was estimated from TCE initiation using the Kaplan–Meier method and compared using the log-rank test. Univariate and multivariable Cox proportional hazards models were used to identify predictors of PFS in the entire cohort and the subcohorts of BCMA TCEs and talquetamab (Talq). Results We analyzed 943 treatment initiations with TCEs in RRMM, comprising 577 BCMA-directed TCEs [teclistamab (n=436) and elranatamab (n=141)] and 366 talquetamab initiations. The median follow-up from TCE initiation was 13.4 months (95% CI: 12.5–14.2) and median age was 68 years (interquartile range 61-75 years). Two ore more HRCAs were noted in 30% of the cohort (34% in Talq vs. 28% in BCMA TCEs, p=0.04), EMD was present in 21% of patients (26% in Talq vs. 18% in BCMA TCEs, p=0.002), and 45.5% of patients had FHRMM (47% in Talq vs. 45% in BCMA TCE, p=0.54). The median prior lines of therapy was 6 (interquartile range: 5-8), with 92% being triple-class refractory (TCR); 60% received prior BCMA-directed therapy (85% in Talq vs. 45% in BCMA TCE, p<0.0001) and 45% had prior CAR-T in 45% (57% in Talq vs. 37% in BCMA TCE, p<0.001). The best overall response rate (ORR) was 67.1 % for the entire cohort (66.4% for BCMA cohort and 68.2% for Talq), with 32.5% patients achieving a ≥ complete response. The median PFS was 7.7 months (95% CI: 6.7–8.6) for the entire cohort, with a median PFS of 10.1 months (95% CI: 7.5-13.4) for teclistamab and 10.1 months (95% CI: 3.9-NR) for elranatamab. In the more heavily pretreated talq cohort, the median PFS was 6.4 months (95% CI: 5.1-7.5). In a univariate analysis (UVA), several HRCAs were associated with inferior PFS−del(17p) (HR 1.59), t(4;14) (HR 1.43), del(1p) (HR 1.54), and ≥2 HRCAs (HR 1.64), all p<0.01. Apart from HRCAs, adverse disease characteristics included FHRMM (HR 1.20) and EMD (HR 1.46); all p<0.05. Among laboratory markers, hemoglobin <9 g/dL (HR 2.10), platelet count <75 ×10⁹/L (HR 1.96), and elevated ferritin (≥600 ng/mL; HR 2.17) (all p<0.01) were prognostic for PFS. ECOG ≥2 (HR 1.62), prior BCMA-directed therapy (HR 1.56), and prior CAR-T (HR 1.44) (all p<0.001) were also associated with inferior PFS. In a multivariable analysis (MVA), prior BCMA therapy (HR 1.72, p<0.0001), ferritin >600 ng/mL (HR 1.68, p<0.0001), hemoglobin <9 g/dL (HR 1.53, p=0.001), ECOG PS ≥2 (HR 1.52, p=0.0009), del(17p) (HR 1.44, p=0.0034) and FHRMM (HR 1.26, p=0.047), were associated with inferior PFS. Within the talq cohort (n=366), EMD (HR 1.64), del(17p) (HR 1.42), del(1p) (HR 1.54), FHRMM (HR 1.34), ECOG ≥2 (HR 1.56), ferritin >600 (HR 1.88), hemoglobin <9 g/dL (HR 1.6), platelet count <75 ×10⁹/L (HR 1.36) and leukopenia <0.25 x 10⁹/L (HR 1.52) were adverse prognostic markers on UVA. A MVA confirmed the independent impact of ferritin >600 ng/mL (HR: 1.77), ECOG ≥2 (HR 1.61) and functional high-risk status (HR 1.52) on PFS, whereas del(17p) and EMD were trending toward significance. Within the BCMA TCE cohort (n=577), prior BCMA therapy (HR 1.9), ferritin >600 (HR 1.79), ECOG ≥2 (HR 1.55), Hb <9 g/dL (HR 1.54), and del(17p) (HR 1.52) were independently associated with inferior PFS on a MVA.Conclusions: In this large real-world cohort of TCE, outcomes varied by fitness, disease biology, and treatment history. The ECOG PS, elevated ferritin, functional high-risk status and del(17p) were consistently associated with inferior PFS. Prior BCMA exposure was an independent risk factor for inferior PFS in the BCMA TCE cohort, but not with talquetamab.

Abstract Background: Prolonged cytopenias are a well-recognized complication following CAR-T therapy, leading to increased morbidity and healthcare utilization. Autologous SCB offers a potential strategy to promote hematologic recovery. We conducted a retrospective multi-institutional analysis across 18 centers comparing outcomes of SCB versus supportive care alone in RRMM patients who experienced prolonged cytopenias >30 days after CAR-T infusion. Methods: Patients were included if they received SCB within 1 year after commercial CAR-T between 6/2021 and 3/2024. To identify matched controls, we reviewed other CAR-T recipients from the same consortium and selected those with an absolute neutrophil count (ANC) of <0.72x109/L and platelet count of <21K at day 30 post-infusion-thresholds representing the 75th percentile of cytopenia severity in the SCB cohort. These criteria ensured control patients had comparable hematologic toxicity but without SCB. Hematologic recovery in the SCB cohort was assessed using the CIBMTR engraftment criteria. For the non-SCB (nSCB) group, cell counts were analyzed cross-sectionally at day 90 post-CAR-T and compared to the SCB cohort with Kruskal Wallis tests. Progression-free survival (PFS) and overall survival (OS) were evaluated using Kaplan Meier methods. Results: Of the 590 CAR-T recipients, 91 patients (15.4%) developed prolonged cytopenias; 39 patients received SCB and 52 did not. SCB patients more frequently had ISS stage III disease (23.1% vs. 11.5%), exrtamedullary disease (59% vs. 46.2%) and penta-refractory status (43.6% vs. 34.6%). The median number of prior lines of therapy was 6 in both cohorts. Thirteen patients (33.3%) in the SCB and 11 (21.2%) in the nSCB received high intensity infusional chemotherapy (DCEP/PACE/HyperCVAD). Pre-CAR-T cytopenias tended to be less frequent in the SCB vs. nSCB cohort: ANC <1000 in 5.1% vs. 13.5%, Hgb <8 in 23.1% vs. 21.2%, and platelets <50K in 28.2% vs. 40.4%. Median plasmacytosis in the bone marrow prior to CAR-T in the SCB group was 35% and 47.5% in the nSCB group. In the SCB cohort, 2 patients harbored DNMT3A mutations, one of whom had CCUS. Ide-cel was administered in 64.8% and cilta-cel in 35.2% of all patients. The rates and grades of cytokine release syndrome did not differ between groups. Six patients (15.4%) had HLH in the SCB group vs. none in the control group. All (100%) SCB patients received growth factor support; 58% also received TPO agonists. In the nSCB group, 43 patients (82.7%) received growth factor, and 16 patients (30.8%) received TPO agonists. Out of 24 pre-SCB bone marrow biopsies available, only 1 patient had relapsed MM while the remainder had hypocellular marrows. Median CD34+ cell dose was 2.93 million/kg (range: 1.76-23.55) administered at a median of 53 days post-CAR-T (range 24-265). All but one patient (97.4%) in the SCB group achieved hematologic recovery; median time to recovery was 24 days (range 9-87). No new toxicities attributable to SCB were observed. On day 90 post CAR-T infusion, SCB patients had higher median ANC (2.12 vs. 1.59x109/L, p=0.277), Hgb (10.6 vs. 8.7g/dL, p=0.002), and platelet counts (135 vs. 35K/L (p<0.001). Minimal residual disease negativity was achieved in 82.4% (SCB) vs. 83.3% (nSCB). Infections occured in 53.8% and 48.1% of SCB and nSCB cohorts. All serious infections occurred prior to SCB. There were 12 deaths in the SCB group (7 from disease progression, 2 from infection, 1 from neurotoxicity (NT), and 1 unknown) and 27 in the nSCB group (22 from progression, 3 from infection, 1 from HLH, 1 from NT). After a median follow-up period of 12.6 months in the SCB cohort and 11.6 months in the nSCB arm, the mPFS was 11.0 months and 8.2 months, respectively. The mPFS was 10.6 months (SCB) and 5.8 months (nSCB) (p=0.216), and 11.0 months (SCB) and 10.9 months (nSCB), for ide-cel and cilta-cel treated-patients, respectively. Median OS was not reached vs.12.3 months in the SCB vs. nSCB groups, respectively. Conclusion: Overall, SCB was safe and effective in promoting rapid hematologic recovery in nearly all patients. Compared to controls, SCB recipeints had significantly higher Hgb and platelet levels by day 90 post-CAR-T infusion. SCB was associated wih a near doubling of PFS in patients who received ide-cel, though interpretation is limited by non-randomized design and small sample size. Further study is needed to optimize paient selection, timing, and integration of SCB into CAR-T care.

Abstract Introduction: Ciltacabtagene autoleucel (cilta-cel) has shown high efficacy in relapsed MM, but further efforts are needed to mitigate non-ICANS delayed neurotoxicity (DNT) and non-relapse mortality (NRM). Identifying risk factors associated with DNT and NRM may help with risk mitigation by aiding the development of interventions for potentially modifiable risk factors and also help with clinical decision making. Methods: In this multi-center retrospective study from the US MM Immunotherapy Consortium, we evaluated 761 patients treated at 15 centers receiving standard of care cilta-cel for relapsed MM between May 2022 to December 2024. Risk factors for DNT, particularly Parkinsonism and NRM were evaluated in by univariable and multivariable analysis. Any NRM events occurring after disease progression were censored for NRM evaluation. Results: The median age of the cohort was 65 years old (range: 30-88), median prior lines of therapy (pLoT) were 5 (range: 1-23). Cilta-cel was used in earlier relapse (1-3 pLOT) in 16% (n=120) patients. High-risk cytogenetics [del 17p, t(14;16) or t(4;14)] were present in 39%, with extramedullary disease (EMD) in 27% and R-ISS stage III in 18% of patients, respectively. Majority of patients (86%) received bridging therapy with response to bridging (≥ partial response, PR) seen in 33% of patients, respectively. Median follow up was 10.1 months, with response rate of 92% and CR rate of 70%. DNT was seen in 10% (n=75) of patients, with distribution as follows: Parkinsonism in 2.9% (n=22), cranial nerve palsy in 4.6% (n=35) and other DNT in 2.4% (n=18), with some patients manifesting more than one type of DNT. Risk of DNT was higher in patients who did not respond to bridging therapy (Any DNT: 12% vs 6%; Parkinsonism: 5% vs 0.5%, both p<0.05) Of the 22 cases of Parkinsonism, 21 patients (95%) did not respond to bridging, even though they achieved a post CAR-T response with ORR of 91% and ≥ CR in 68%. Absolute lymphocyte count (ALC), a surrogate measure of CAR expansion was higher in patients who developed DNT, particularly Parkinsonism, including ALC at days 7,14,21,28 and as peak ALC in the first month post cilta-cel (p<0.05 for all). Median peak ALC for patients with vs without Parkinsonism was: 5.88 vs 1.17/uL (p<0.001). We evaluated risk of Parkinsonism with various thresholds of peak ALC expansion. Amongst patients who developed Parkinsonism vs. not, peak ALC was as follows, > 1000/uL: 100% vs 57%, > 2500/uL: 73% vs 19% and > 3000/uL: 68% vs 14% (all p<0.001). The absolute risk of Parkinsonism with ALC > 3000 vs ≤ 3000/uL was 12% vs 1%, p<0.001; for ALC 2500 vs ≤ 2500uL was 9% vs 1%, p<0.001. On multivariable analysis, peak ALC > 3000/uL (OR: 12.7, p<0.001) and non-response to bridging therapy (OR: 9.9, p=0.03) were independent risk factors for developing Parkinsonism after cilta-cel. After cilta-cel, 1 and 2 year NRM estimates were 9% and 10%, respectively. Amongst 63 (8%) patients experiencing NRM events, the most common cause of NRM was infectious complications (35, 56%), followed by acute immune-mediated adverse events (AEs) like CRS, ICANS, IEC-HS in 14 (22%), delayed immune mediated AEs like DNT and colitis in 6 (9.5%), second cancers in 5 (8%) and other causes in 3 (5%) patients, respectively. When evaluating the timing of NRM events, the risk of infection related mortality remained relatively stable in the first year, though immune mediated toxicty deaths were uncommon after 6 months, while SPMs were uncommon within the first 6 months. On multivariable analysis, non-response to bridging (HR 2.41, p=0.046), poor performance status ≥ 2, high-risk cytogenetics and age ≥ 70 years were independent predictors for NRM. Conclusion: In a large cohort of over 750 patients receiving cilta-cel, we identified potentially modifiable risk factors for Parkinsonism and NRM. Non-response to bridging therapy and peak ALC > 3000/uL were independent predictors of developing Parkinsonism. Peak ALC of > 2500/uL and > 3000/uL were associated with 9% and 12% absolute risk of Parkinsonism. This indicates that peak ALC of 2500/uL or 3000/uL in the first month after cilta-cel may be a potential biomarker to identify patients for pre-emptive interventions such as steroids that can suppress rapid CAR expansion and perhaps decrease the risk of Parkinsonism. In addition, we need to focus on effective bridging strategies to further decrease the risk of Parkinsonism, as well as NRM with cilta-cel.

Abstract Introduction Ciltacabtagene autoleucel (cilta-cel) has demonstrated unprecedented response rates and progression-free survival (PFS) in relapsed/refractory multiple myeloma (RRMM), but a proportion of patients experience early relapse. Identifying these patients is essential to guide future therapeutic strategies, such as enhanced bridging therapy or consolidation, while avoiding overtreatment in those likely to achieve durable disease control. Methods We conducted a multi-center study of patients treated with cilta-cel at 15 U.S. academic centers. Outcomes were evaluated based on high-risk (HR) features, including functional HR disease (FHR; relapse within 18 months of first-line therapy initiation), true extramedullary disease (EMD), traditional HR cytogenetics as defined in CARTITUDE-1 [deletion 17p, t(4;14), t(14;16)], and a 2024 IMS-IMWG-adapted HR definition (deletion 17p; t(4;14) or t(14;16) with gain 1q or deletion 1p; and gain 1q with deletion 1p). Multivariable Cox regression was used to examine the association of HR features (FHR, adapted IMS-IMWG HR, and EMD, individually and collectively) with PFS while adjusting for baseline ferritin, prior BCMA, and ECOG performance status (PS ≥2). Among patients with ≥18 months of follow-up, we evaluated predictors of early relapse (≤18 months post infusion) using logistic regression. Results Our cohort included 598 patients treated with cilta-cel between 5/2022 and 12/2024 who had available data on all HR features. The median age was 65 years (range 33-83), and the median prior lines of therapy (pLOT) was 5 (range: 1-18, 84% with >3 pLOT); 8% had received prior BCMA-directed therapy, and 27% were penta-refractory. Most patients (88%) received bridging therapy and 30% achieved ≥ partial response. In our cohort, 33% (n=195) had FHR, 43% (n=258) had traditional HR cytogenetics, 42% (n=253) had adapted IMS-IMWG HR disease, and 11% (n=64) had EMD. Median follow up was 10.6 months (range 0.4-34.1). Overall response rate (ORR) and complete response (CR) rates were lower in patients with vs without HR features: FHR (ORR: 89% vs 94%, CR: 61% vs 75%), traditional HR (ORR: 90% vs 94%, CR: 65% vs 74%), adapted IMS-IMWG HR (ORR: 91% vs 94%, CR: 64% vs 75%) and EMD (ORR: 77% vs 94%, CR: 61% vs 71%). Corresponding 12-month PFS was also lower in patients with vs without HR features: FHR (55% vs 79%), traditional HR (63% vs 78%), adapted IMS-IMWG HR (61% vs 80%) and EMD (59% vs 73%). ORR, CR rate, and 12-month PFS in patients without any HR features compared to those with ≥1 HR feature were 96% vs 90%, 81% vs 64%, and 83% vs 65%, respectively. In multivariable models, each HR feature (FHR, adapted IMS-IMWG HR, and EMD) was independently associated with inferior PFS after adjusting for baseline ferritin, prior BCMA, and ECOG PS ≥ 2. However, because early relapse cannot always be identified a priori based on traditional risk factors, we sought to identify predictors of relapse within 18 months of cilta-cel in a subset of patients with ≥18 months of follow-up (N=247; infused by 12/2023). Notably, while FHR (OR=3.04, 95% CI=1.59-5.89) and adapted IMS-IMWG HR (OR=2.07, 95% CI=1.10-3.89) were independently associated with odds of relapse within 18 months, EMD was not (OR=0.90, 95% CI=0.32, 2.40) when accounting for prior BCMA, ECOG PS ≥ 2, and baseline ferritin. We also used a time-varying Cox model to examine each HR feature associated with PFS at two time periods, <18 and ≥18 months, while adjusting for baseline ferritin, ECOG PS, and prior BCMA. We confirmed that FHR and adapted IMS-IMWG HR were both associated with relapse <18 months (HR=2.05, 95% CI=1.48-2.83 and HR=1.56, 95% CI=1.11-2.19) but not in the ≥18-month time period (HR=0.70, 95% CI=0.19-2.59 and HR=0.76, 95% CI=0.24-2.40). The magnitude of the association for EMD with PFS was similar across both time periods (<18 months HR=1.67, 95% CI=1.09-2.57 and ≥18 months HR=2.17, 95% CI=0.45-10.40). Conclusion While cilta-cel leads to high response rates and durable PFS in RRMM, a subset of patients with FHR and adapted IMS-IMWG HR remains at increased risk for early relapse. In this large multi-center cohort, we describe PFS outcomes across high-risk subgroups and identify key predictors of relapse within 18 months of cilta-cel. These findings inform risk-adapted therapeutic strategies and interventional trials, including bridging, consolidation, or maintenance approaches, to improve outcomes in the highest-risk RRMM patients.

Abstract Introduction: NAVD has become a standard-of-care for frontline (1L) treatment (tx) of advanced stage cHL, based on the results of the S1826 study. S1826 demonstrated a 1-year progression free survival (PFS) of 94% for NAVD compared to 86% for brentuximab vedotin-AVD, which remained durable at 2 years (Herrera et al, NEJM 2024). Adverse events (AEs) and efficacy have not been reported in patients (pts) treated with NAVD outside of a clinical trial. Hence, we sought to evaluate safety profile and efficacy outcomes of pts with cHL treated with 1L NAVD in a real-world setting (RWS). Methods: In this multicenter retrospective cohort study, we included pts ≥18 years with cHL treated with 1L standard of care NAVD between 2023 and 2025 at 20 US academic sites. The safety evaluable cohort received at least 1 cycle of NAVD and included pts who have not completed tx. The efficacy evaluable cohort had completed 6 cycles of tx including end of treatment (EOT) PET-CT and included pts who intended to complete tx but died or discontinued due to progressive disease or AEs. The primary endpoint was EOT overall response rate (ORR). Secondary endpoints included EOT complete response rate (CRR), PFS and overall survival (OS). PFS and OS were calculated from the start date of tx and analyzed using the Kaplan Meier method. Results: A total of 311 pts with cHL were treated with NAVD with 26% of pts with tx ongoing (n=83) and 73% with tx completed (n=228). Baseline demographics included 55% male pts, 60% with stage IV disease (stage IIB, n=4) and 84% with nodular sclerosis subtype. Median age was 37 years (range 18-88), 29% had bulky disease (>7.5 cm), 28% were EBV positive (n=74/268), 8% had history of an autoimmune disease, and 31% had an IPS 4-7. G-CSF was given in 64% of pts. All patients were safety evaluable. Tx was interrupted (any length) in 24%, reduced in 12%, and discontinued in 14%. The most common reason for dose reduction was neuropathy in 4%. Nivolumab was discontinued in 10% and all therapy in 3.7% due to toxicity. Any AE and any grade 3 or higher AE (>G3) were observed in 92% and 62%, respectively. Neutropenia of any grade occurred in 68% (48% >G3), infection in 25% (10% >G3), and neuropathy in 30% (2.8% >G3). Hospitalization for an AE occurred in 20% (4.5% febrile neutropenia). Among pts with complete data (n=305), any immune related AE (irAE) occurred in 78 pts (25.6%) with any >G3 irAE in 23 pts (7.5%). The most common irAEs included hypothyroidism (7.9%, all grade 1-2), hepatotoxicity (1.6% G1/G2, 3.3% >G3), inflammatory arthritis (3% G1/G2, 0.6% >G3), rash (2.6%, all grade 1-2), and colitis (1% G1/G2, 1% >G3). Other notable >G3 irAEs included adrenal insufficiency (n=2), AKI/ATN (n=1), myocarditis (n=1), diabetes (n=1) and pancreatitis (n=1). Of 84 irAE events, 47 (56%) have had complete resolution. Among all pts, 14.4% (n=45) required systemic steroids at any time (intravenous in 4.1%), 3.2% (n=10) require ongoing steroids/immunosuppression and 8.3% other therapy for an irAE (n=23 levothyroxine, n=1 hemodialysis, n=1 heart failure tx, n=1 insulin). Among all pts, 265 (85%) had an interim PET-CT after 2-4 cycles. The ORR and CRR at interim PET-CT were 97% and 78%, respectively. In the efficacy evaluable population (n=228), the EOT ORR and CRR were 96% and 90%. The median follow up was 10.2 mo (range 0.27-28.52). The 1-year PFS and OS estimates were 93.8% (95% CI: 90.8-98.4%) and 99.1% (95% CI: 97.9-100%), respectively. In multivariable analysis (MVA), only IPS score (OR 0.6, 95%CI: 0.59-0.60) was associated with lower CRR. In Cox univariable analysis, EBV+ status (HR=14.8, 95% CI: 3.2-69.2), IPS score (HR=1.5, 95% CI: 1.0-2.2), and ESR (HR=1.02, 95% CI: 1.00-1.04) were associated with worse PFS. Among the 11 pts with progression/relapse, 9 were primary refractory. 10 pts were started on second line (2L) therapy, and all pts are alive (1 pt pending 2L tx initiation). There were 2 deaths: one related to infectious complications and other unknown and both occurred after the first cycle of therapy. Conclusions: Pts treated with NAVD in a large RWS showed comparable response rates and 1-year survival outcomes to those in the pivotal S1826 trial. Most AEs were similar and grade 1-2, but close monitoring of irAEs is necessary given the potential long-term toxicity of checkpoint inhibitors and potential for ≥G3 irAEs (7.5%) in this young patient population. Our data supports the use of NAVD for 1L advanced stage cHL.